1. Field of the Invention
The present invention relates to a recording apparatus. More particularly, the present invention provides an apparatus that can record a long moving picture without using a large-capacity memory in order to accumulate management information.
2. Description of the Related Art
Recording apparatuses which record moving picture data on random access media, such as magnetic disks and memory cards, are known. In these apparatuses, moving picture data is treated as moving picture files, and the moving picture files are written in and read from the recording media under management by a predetermined file system.
A file system refers to a structure type used to create files and folders in recording media or to manage deletion and movement of the files and the folders. A file-name addition method and a file size are specified in each file system. As such file systems, an FAT (File Allocation Table) and a UDF (Universal Disc Format) are known.
For example, in a recording apparatus adopting a FAT, when the size of a moving picture file that is now being recorded reaches the maximum size specified by the FAT, the file is divided. In other words, recording of the moving picture file is stopped before completion, e.g., halfway, and a new file is created so as to continue recording of moving picture data.
Japanese Patent Laid-Open No. 2005-260440 proposes that a moving picture file is divided and recorded every time a predetermined time elapses after recording of moving picture data starts.
Further, an AVCHD (Advanced Video Codec High Definition) method has recently been proposed as a standard of consumer recording apparatuses that record high-definition (HD) moving pictures having more pixels in one picture than known standard pictures (VGA size).
In an AVCHD method, moving picture data is coded according to an MPEG-4 AVC/H.264 format, and is recorded as a moving picture file on a recording medium. In addition to the moving picture file, a clip information file including management information about the moving picture file is created and recorded. This clip information file contains information about the position of a specific picture (the first intra-frame in each GOP (Group of Pictures)) in moving picture data. The clip information file is used to play back the moving picture data at a fast speed and to access a designated position.
Since the position of an intra-frame in moving picture data can be known only after the completion of recording, management information is usually held in an internal memory of the apparatus during recording of the moving picture data. After recording of the moving picture data is completed, all management information held in the memory is recorded as a clip information file.
In such a recording apparatus, if power is unpredictably shut down during recording, a clip information file is not recorded. Thus, it is difficult to play back recorded moving picture data.
It is conceivable to divide and record a moving picture file at regular time intervals and to record a clip information file every time a moving picture file is divided and recorded, as disclosed in Japanese Patent Laid-Open No. 2005-260440.
In this case, however, a clip information file about a moving picture file that is being recorded at power shutdown is also not recorded. Therefore, it is difficult to play back the moving picture file.
Accordingly, management information can be accumulated in a nonvolatile memory and be stored when power is shut down. In this case, the management information can be read out from the memory when power is restored, and can be recorded as a clip information file.
Unfortunately, since the size of management information is proportional to the length of recording time of the corresponding moving picture, when a long moving picture is recorded, a large-capacity memory is necessary to accumulate management information about the picture.
Therefore, when management information is held in the nonvolatile memory, as described above, it is necessary to prepare a large-capacity memory so as to hold management information corresponding to a long moving picture. This increases the cost of the recording apparatus.